The purpose of this study was to investigate the effect of using science and engineering practices in biology on students' achievement and attitudes toward biology. Hence, the study investigated the following questions: A) What are the effects of implementing scientific and engineering practices as compared to structured inquiry on eighth grade students’ achievement in cellular biology? B) What are the effects of implementing scientific and engineering practices as compared to structured inquiry on eighth grade students’ attitudes toward biology? C) What are the effects of implementing scientific and engineering practices in teaching about cellular biology on eighth grade students’ design skills? The design of this study was quasi-experimental. Participants in this study were sixty-five eighth grade students in a K-12 international school in Lebanon. The classes were randomly assigned to a control and an experimental group. The experimental group was taught using science and engineering practices instruction presented in the K-12 Framework in the Next Generation Science Standards (NGSS) (2013). Meanwhile, participants in the control group received inquiry-based instruction throughout their activities. Both groups studied the cellular biology unit which was taught by the same teacher for five weeks. Data sources for the study included two cellular biology concept tests used as pre-tests and post-tests, two achievement tests, and a biology attitude scale (BAS) which was used to measure changes in students’ attitudes toward biology in both groups. Moreover, students’ written responses during an engineering design assessment were collected and analyzed in order to determine the proficiency level of students’ engineering design skills. Finally, students’ responses to interviews to gauge students’ opinions about the teaching approaches were used in the study. The results of the first and second concept tests showed that students in the experimental group achieved higher than students in the control group but the difference was not significant. Likewise, students’ scores on the two biology achievement tests that were administered during the study did not show significant gains in achievement between both groups. However, results of the first achievement test showed that students’ scores on the high cognitive level questions in the experimental group were significantly higher than the control group. In depth analysis of the two-tier concept tests was carried out where the number of correct answers, reasons and both were computed for each test item. Results showed that the intervention improved the achievement of students in certain concepts but not in others indicating the possibility that a number of concepts included in the concept tests were abstract, which requires that teachers use strategies that help them to explain the concepts at the molecular level. Furthermore, the level of proficiency in design skills was higher in the experimental group than in the control group in assessing designs and explaining the designs functionality. Analysis of the results of the biology attitude scale showed that there were no significant differences in attitudes between the two groups. Finally, students showed positive but different opinions regarding the instructional approaches. Implications to practice as well as recommendations for further research are discussed in light of these findings.
(Author's abstract)